Extrusion mold and method of use

ABSTRACT

In one embodiment of the invention a mold system and method of use are provided such that aqueous starch-based compositions and baked goods articles that use the conversion of water to steam may be produced using an extruder that allows the venting of such gases and/or steam. The extruder is vented in such a way as to allow steam to escape, but retain the composition until the exit end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/648,129, filed Dec. 28, 2006 and now pending, which is acontinuation-in-part of U.S. patent application Ser. No. 10/608,441filed Jun. 27, 2003, entitled “Method for Use in Baking Articles ofManufacture and Mold for Use in Said Method,” and U.S. patentapplication Ser. No. 10/928,602 filed Aug. 26, 2004, entitled“Composition for Use in Biodegradable Articles and Method of Use,” whichclaims the benefit of U.S. Provisional Patent Application No. 60/498,129filed Aug. 26, 2003, entitled “Mix Formulation for Use in BiodegradableArticles and Method of Use,” and U.S. Provisional Patent Application No.60/498,396 filed Aug. 27, 2003, entitled “Mix Formulation for Use inBiodegradable Articles and Method of Use.” The entirety of each of theseapplications is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to systems and methods forcreating extruded products while venting steam and/or gases during theextrusion process.

BACKGROUND OF THE INVENTION

The pressure to use biodegradable disposable packaging has been steadilyincreasing in the last decade. As recently as March, 2003, Taiwan hasoutlawed the use of Styrofoam in disposable packaging. Even China'smajor cities such as Beijing and Shanghai have outlawed the use ofStyrofoam materials in disposable packaging. Various attempts have beenmade in the prior art to manufacture starch based disposables for use infood service items such as trays, plates, and bowls. Some methodsinclude producing starch based packaging that has materials vented inexcess of the final product as can be evidenced when one inspects thefinished product. However, these technologies use male and female moldsand not extrusion dies. Attempts to extrude starch do not includeventing during the extrusion process, and instead include injectiongases in an attempt to foam the starch.

Further, the majority of the existing extrusion processes using starchare geared towards producing thick sheeted materials that are thenbonded together to form packaging materials that replace thickStyrofoam. Examples are protective packaging for shipping televisionsets or other similar electronic or heavy systems. Unfortunately,existing efforts have not been successful for producing articles such astoilet paper rolls, chop sticks, or straws primarily due to theinability to reduce pressures during the baking-extrusion process.

Accordingly, there is a need for improved systems and methods forextruding materials while continually venting gases during the extrusionprocess without any substantial material losses.

SUMMARY OF THE INVENTION

In one embodiment of the present invention a method of extruding amaterial is provided comprising the steps of providing an extrusion headhaving a plurality of venting gaps for venting a gas; providing anextrusion mixture comprising fibers and water to the extrusion head;extruding the mixture through the extrusion head wherein the step ofextruding comprises heating the mixture within the extrusion head suchthat the gas is release from the mixture; venting the gas from theextrusion head through the plurality of venting gaps such that theremaining mixture is substantially retained by the extrusion head.

In another embodiment, an extrusion head is provided comprising aplurality of venting gaps, wherein the venting gaps are dimensioned toallow for the venting of a gas but substantial retention of theremaining material to be extruded during extrusion and wherein theventing gaps are both radial and axial and the extrusion head ismulti-piece.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to fully understand the manner in which the above-reciteddetails and other advantages and objects of the invention are obtained,a more detailed description of the invention will be rendered byreference to specific embodiments thereof which are illustrated in theincluded drawings. Understanding that these drawings depict only typicalembodiments of the invention and are not therefore to be considered aslimiting of its scope, the invention will be described and explainedwith additional specifity and detail through the use of accompanyingdrawing in which:

FIG. 1 is a view of a basic venting feature of an embodiment of thepresent invention.

FIG. 2 is a view of a cross section of an extruder head of an embodimentof the present invention.

FIG. 3 is a perspective view of a venting feature applied in an axialand trans-axial fashion to the extruder head of an embodiment of thepresent invention.

FIG. 4 is a cross section view of an extruder head of an embodiment ofthe present invention with a venting features with a center mandrel usedto allow the formation of tube shapes.

FIG. 5 is a perspective view of an extruder head of an embodiment of thepresent invention showing a mix with or without fibers going through theextruder and exiting formed on the other end.

FIG. 6 is a perspective view of an extruder head of an embodiment of thepresent invention showing continuous fibers and mix being introduced tothe extruder and exiting formed on the other end..

FIG. 7 is a cross section view of a formed product of an embodiment ofthe present invention with continuous fibers in a relatively straightconfiguration in a tube and rod configuration.

FIG. 8 is a perspective view of the extruder of an embodiment of thepresent invention being fed fibers that are braided or knitted thenintroduced into the opening along with the starch mixture.

FIG. 9 is a perspective exploded view of the various pieces of anembodiment of the present invention that are designed in such a way asthey fit into an outer sleeve that would hold them together but stillallow venting of the steam or gases.

DETAILED DESCRIPTION

The following description of the invention is intended to illustratevarious embodiments of the invention. As such, the specificmodifications discussed are not to be construed as limitations on thescope of the invention. It will be apparent to one skilled in the artthat various equivalents, changes, and modifications may be made withoutdeparting from the scope of the invention, and it is understood thatsuch equivalent embodiments are to be included herein.

In an embodiment of the present invention, the characteristics of bakedgoods are used to provide high efficiency systems and methods forextruding starch-based articles as well as similar behavior materials.The systems and methods of the present embodiment accomplish the abilityto extrude thin and thick walled extrusions that could not previously beproduced due to the inability to vent gases during the extrusionprocess.

In the present embodiment, vents may be added within an extrusiontunnel, axially and/or through a cross section. Thus, referring to FIGS.1-3, one embodiment of the inventive systems comprises a multi-pieceextrusion head 10. The extrusion head 10 comprises one or more axialventing gaps 20 and/or radial venting gaps 30 that extend along themating perimeter of the different pieces of the extrusion head 10. Thesize of the venting gaps 20, 30 can be constant or vary and arepreferably from between about 0.001″ to about 0.006″ to allow steamand/or other gases to escape during the extrusion process, but containthe material to be extruded. The extrusion head 10 may also compriseventing gaps 20, 30 along the axis of the extrusion as well as radiallybetween multiple pieces that are then attached together or may compriseonly axial venting gaps 20 or only radial venting gaps 30.

In one aspect of the present embodiment the composition to be extrudedcan be water, alcohol or other liquid based. The composition may or maynot contain additives such as fibers to improve the properties of thecomposition.

According to another embodiment of the invention, during the extrusionprocess, fibers can be chopped up and mixed in an extrusion mixture orfibers can be continuous and pulled through as is performed in compositepulltrusions. For pulltrusions, the fibers are pulled through a materialflow opening of the extruder and are baked directly into the starchmixture. This can form a very axially strong product since the fibersare continuous.

According to another embodiment of the invention, the fibers can beknitted together to form different shapes that are then pulled throughthe extruder and baked into the starch. This method allows for biaxiallystrong extrusions. It also allows the user to customize requiredstrength solutions by producing a fiber matrix that is then baked intothe starch matrix.

According to another embodiment of the invention, the addition of acenter mandrel with or without venting features on this mandrel andheated or unheated which would allow for the formation of tubes such aspaper roll centers, toilet paper centers, and straws.

One feature of some embodiments of the invention is that the number ofventing gaps can be customized, i.e., increased or reduced in numbers orsize, to better control the steam and gas release process. It isimportant to note that not only round shapes but squares, rectangles,octagonal, namely, any cross-section that can be extruded, could bedeveloped for this process. As previously mentioned, the addition ofcenter mandrels could help in forming tube like sections instead ofpurely solid shapes.

Methods according to some embodiments of the invention generallycomprise the steps of mixing at least water and starch together to forma starch-based composition then extruding the composition through thespecial die heads. The heat starts to bake the starch which in turnforms a skin wherever it comes into contact with the heated extrudersurfaces. In addition, the heat turns the water in the composition tosteam which is allowed to escape via the venting features. The mixturecan have premixed fibers in it or continuous fibers that can also bestitched together or weaved in a shape to improve the overall strengthof the finished product.

These and other features of embodiments of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the invention as set forthhereinafter.

In another embodiment of the present invention mold systems and methodsof use are provided such that aqueous starch-based compositions andbaked goods articles that use the conversion of water to steam may beproduced using an extruder that allows the venting of such gases and/orsteam. The extruder is vented in such a way as to allow steam to escape,but retain the composition until the exit end.

More particularly, some embodiments use the physical property of starchand other baked goods to allow the release of steam without releasingthe composition. When the mixture first contacts the heated surfaces ofthe extruder, they form a skin and the water in the mixture starts toturn to steam. This method of allowing the venting of the steam atmultiple areas along the extrusion path allows for more dense productsthat can withstand much higher forces. By adding steam release gapsusing the several different methods describes herein, the baking timecan be reduced thus increasing output.

By methods of the present embodiment one may produce tube and otherextruded shapes that would be cheaper than existing paper and plasticproducts. Moreover, the overall process tends to be relatively benignand does not use the harsh chemicals normally associated with paper orplastic products.

In another embodiment of the present invention, the above extrusionconcept may be applied to any material that can be placed in a cavitywhich when exposed to the heated surface produces a skin that issemi-permeable to the liquid being turned to gas and is not limited toaqueous based mixtures. Moreover, the mixtures can be edible ornon-edible and could include various components for modifying theproperties of the mixture, such as the addition of scents or othermaterials.

Referring to FIG. 4, a cross-section of an extruder head having ventinggaps 100 and an inner mandrel 110 that would be used for tube structuremanufacturing is shown.

Referring to FIG. 5, a trimetric view showing the extrusion of a tubestructure 200 through an extruder head 210 from mix 220 with fiber 230.

Referring to FIG. 6, a trimetric view showing a mix 300 and continuousfibers 310 being introduced to the extruder head 320 to produce anextrusion 330. Referring to FIG. 7 a, a cross section of the extrusion330 is shown demonstrating fiber 310 orientations for a tube extrusion,and referring to FIG. 7 b, a cross section of the extrusion 330 is showndemonstrating fiber 310 orientations for a rod configuration. As canbeen seen in FIGS. 7 a and 7 b, the fiber 310 is oriented along thelength of the tube or rod.

Referring to FIG. 8, a continuous fiber 400 being knitted into a generalcohesive shape 410 is shown being inserted into a mix 420 which is thenextruded through the extruder head 430 to form the extrusion 440.

Referring to FIG. 9, a trimetric view of an extruder head 500 that maybe inserted into a pipe 510 or similar to hold the individual pieces ofthe extruder head together is shown.

As stated above, the foregoing is merely intended to illustrate variousembodiments of the present invention. The specific modificationsdiscussed above are not to be construed as limitations on the scope ofthe invention. It will be apparent to one skilled in the art thatvarious equivalents, changes, and modifications may be made withoutdeparting from the scope of the invention, and it is understood thatsuch equivalent embodiments are to be included herein. All referencescited herein are incorporated by reference as if fully set forth herein.

1-11. (canceled)
 12. An extrusion head comprising: a multi-pieceextrusion head comprising at least two pieces, wherein the at least twopieces define at least a portion of an inner cavity that extends thelength of the multi-piece extrusion head; an material inlet on a firstside of the multi-piece extrusion head and a material outlet on a secondside of the multi-piece extrusion head; and a first axial venting gap,the first axial venting gap comprising a first portion extending in asubstantially continuous manner along the length of the multi-pieceextrusion head and in fluid communication with the inner cavity, and asecond portion in direct fluid communication with the first portion,wherein the second portion is wider than the first portion.
 13. Theextrusion head of claim 12 further comprising a plurality of ventinggaps.
 14. The extrusion head of claim 13 further comprising a radialventing gap.
 15. The extrusion head of claim 13 wherein the plurality ofaxial venting gaps comprises the first axial venting gap and at least asecond axial venting gap, the second axial venting gap comprising afirst portion extending in a substantially continuous manner along thelength of the extrusion head and in fluid communication with the innercavity, and a second portion in direct fluid communication with thefirst portion, wherein the second portion is wider than the firstportion.
 16. An extrusion head comprising: a multi-piece extrusion headcomprising at least two pieces, wherein the at least two pieces defineat least a portion of an inner cavity that extends the length of themulti-piece extrusion head; a first radial venting gap, the first radialventing gap comprising a first portion extending in a substantiallycontinuous manner along a circumference of the inner cavity of themulti-piece extrusion head and in direct fluid communication with theinner cavity, and a second portion in direct fluid communication withthe first portion, wherein the second portion is wider than the firstportion.
 17. The extrusion head of claim 16 further comprising a secondradial venting gap.
 18. The extrusion head of claim 17 wherein thesecond radial venting gap comprising a first portion extending in asubstantially continuous manner along a circumference of the innercavity of the extrusion head and in direct fluid communication with theinner cavity, and a second portion in direct fluid communication withthe first portion, wherein the second portion is wider than the firstportion.
 19. The extrusion head of claim 18 wherein at least a portionof the second radial venting gap is formed at a second intersection ofat least two pieces of the multi-piece extrusion head.
 20. An extrusionhead comprising: a multi-piece extrusion head comprising at least twopieces, wherein the at least two pieces define at least a portion of aninner cavity that extends the length of the multi-piece extrusion head;a first axial venting gap, wherein the first axial venting gapcomprising a first portion extending in a substantially continuousmanner along the length of the multi-piece extrusion head and in fluidcommunication with the inner cavity, and a second portion in directfluid communication with the first portion, wherein the second portionis wider than the first portion; and a first radial venting gap, whereinthe first radial venting gap comprising a first portion extending in asubstantially continuous manner along a circumference of the innercavity of the multi-piece extrusion head and in direct fluidcommunication with the inner cavity, and a second portion in directfluid communication with the first portion, wherein the second portionis wider than the first portion, and wherein at least a portion of thefirst axial or radial venting gap is formed at a first intersection ofat least two pieces of the multi-piece extrusion head.
 21. The extrusionhead of claim 20 wherein the first axial venting gap is formed at afirst intersection of at least two pieces of the multi-piece extrusionhead and the first radial venting gap is formed at a second intersectionof at least two pieces of the multi-piece extrusion head.
 22. Theextrusion head of claim 20 further comprising at least a second axialventing gap and at least a second radial venting gap.
 23. The extrusionhead of claim 20 further comprising at least a second axial venting gapand at least a second radial venting gap.
 24. The extrusion head ofclaim 20 further comprising a plurality of axial venting gaps and aplurality of radial venting gaps.